The situation so far is that I have concatenated the template.pot files for each addon and then removed strings that appear in the main gramps.pot file. This new addons.pot file contains the strings that appear for translation in the Addons component on Weblate. The addons.pot can be updated using a script when translations change.
I have also concatenated all the local po files for each language. The copyright statements have also been combined. This was a one off process so that we don’t lose any strings that have previously been updated.
When changes are made in Weblate, combined po files for each language are updated by pull requests. Translations for each addon are then extracted using a script.
The first batch of changes appears to have been merged successfully, but we need to do more testing.
Feedback from translators and addon developers would be welcomed. We need to know if any strings are missing from the addons.pot file. Usability may be another issue. I’m not sure how easy it would be for a translator to translate a single addon for example.